Jig for vane-type magnetrons



July 31, 1956 L. e. COONROD, JR 2,756,709

JIG FOR VANE-TYPE MAGNETRONS Filed April 2, 1946 2 Sheets-Sheet 1 INVENTOR LEW s. COONROD JR;

BY Ma ma M ATTORNEY July 31, 1956 l, s. COONROD, JR 2,755,709

JIG FOR VANE-TYPE MAGNETRONS Filed April 2, 1946 2 Sheets-Sheet 2 FIG.2

INVENTOR LEW G. COONROD JR.

M40449, AL

ATTORNEY United States Patent JIG FOR VANE-TYPE MAGNETRONS Lew G. Coonrod, J12, South Hamilton, Mass., assignor, by mesne assignments, to the United States of America as represented by the Secretary of War Application April 2, 1946, Serial No. 658,932

2 Claims. ('Cl. 113-99) My invention relates in general to electrical apparatus and more particularly to electronic oscillators and means for manufacturing them.

In the generation of extremely high frequency radio waves certain types of oscillator tubes have proved highly valuable. Among these is the magnetron tube which is able to generate radio waves at wavelengths in the centimeter bands.

Several types of magnetron tubes are in current use, two of the most common being the hole-and-slot type magnetron and the vane type magnetron. In the former type of tube the anode electrode consists of a block of metal in which is chambered a plurality of cylindrical resonant cavities each of which is connected to a central cavity by a slot, a resonator and slot together resembling in cross section a keyhole.

The vane type magnetron, on the other hand, has an anode consisting of a metallic ring to which are attached small vanes which lie along radii of the ring, thus dividing the interior of the ring into a number of individual resonators. The vanes do not extend completely to the center of the ring, in order to leave room for the cathode electrode.

Both types of magnetrons are frequently strapped, i. e., the vanes are connected alternately by thin conducting rings in order to increase the frequency separation between the several oscillatory modes set up in the magnetron, in order that the undesired modes may be removed by tuned circuits in the output circuits of the oscillator.

A difiiculty experienced with the hole-and-slot magnetron is that each anode must be machined individually to close tolerances, thereby rendering mass manufacture difiicult. The vane type magnetron, on the other hand, which is assembled rather than cut out of a single block, lends itself more readily to the problems of quantity production.

Accordingly, it is one object of my invention to provide a means for constructing vane type magnetrons.

Another object of my invention is to provide means for constructing vane type magnetrons adaptable to quantity manufacturing methods.

Still another object is to provide means of constructing vane type magnetrons the utilization of which may be confidently assigned to unskilled labor.

Briefly, my invention comprises a jig which is used to hold the various components of a vane magnetron in the proper positions relative to each other during the process of fastening the parts together.

The principles and operation of my invention will be apparent to those skilled in the art upon reference to the following specification and claims, and to the drawings in which:

Fig. 1 shows an exploded view of an embodiment of my invention;

Fig. 2 shows a view of an embodiment of my invention in an assembled form with cut-away portions to show the relative positions of the various parts thereof; and,

2,756,709 Patented July 31, 1956 Fig. 3 shows a perspective view of a completed magnetron anode constructed by a jig as shown in Figs. 1 and 2.

Referring now to Fig. 1, the various parts of my invention are shown in the order of their assembly into working form. Pin 5 is inserted into the central hole in vane holder 6. The vane holder consists of a wide cylindrical base portion, a narrower cylindrical center section, and a tube-like upper portion which is plurality slotted for approximately half its length to accommodate the vanes. Collar 7 is placed over vane holder 6, fitting snugly against the wide portion of the base. Vane retaining ring 8 is placed over vane holder 6. Cap 12 is then placed over pin 5 and retaining nut 13 is screwed onto pin 5 to hold the assembly together. Several holes 14 may be bored through the base of member 6 to facilitate disassembling the jig after use. Pins inserted into these holes from the bottom of the assembly will press against collar 7, driving the magnetron anode shell olf vane holder 6.

Fig. 2, to which reference is now made, illustrates the appearance of the jig when assembled together with the component parts of the magnetron anode under construction. As can be seen, straps 16 and 17 fit into preformed slots in vane holder 6. Vanes 18 are then fitted into the proper slots in vane holder 6, pin 5 maintaining the proper central spacing to allow insertion of a cathode, and vane retaining ring 8 is slipped over the vanes to hold them temporarily in position and in abutment with pin 5. Anode cylinder 20 fits over vane holder 6, forcing ring 8 past the vanes, the thickened portion 21 of the cylinder 20 then holding the vanes in place. Straps 24 and 25 are then fitted into notches in the vanes. Cap 12 holds straps 24 and 25 in place.

The various parts of the jig are constructed preferably of stainless steel and the magnetron components are preferably of copper. The straps and the thickened portion 21 of anode cylinder 20 are silver plated. When the jig and anode components have been assembled, the entire assembly is placed in a hydrogen atmosphere and heated until the silver plating melts. The silver does not adhere to the stainless steel, but flows to the joints between the copper members, and upon cooling forms a tight, highly conducting bond.

When the assembly has been cooled, nut 13 is removed and the structure is broken down by forcing pins up through the holes 14 in the base of vane holder 6 to drive collar 7 up, thereby leaving the vanes and the straps aflixed to the anode ring. The appearance of the completed electrode is illustrated in Fig. 3. In this way magnetron anodes may be made with a high degree of precision and without costly and time-consuming operations.

While there has been described hereinabove what is at present considered to be a preferred embodiment of the present invention, it will be obvious to those skilled in the art that changes and modifications may be made therein without exercise of inventive ingenuity. Hence, I claim all such modifications and adaptations as may fall fairly within the spirit and scope of the hereinafter appended claims.

What is claimed is:

1. A jig for assembling magnetron anode electrodes constructed of a hollow cylindrical member the interior portion of which is partitioned into resonating cavities by metallic vanes disposed substantially along radii of said cylinder, alternate vanes being connected by ring-like conducting members, said jig including a body member having a relatively wide cylindrical lower portion, a narrower cylindrical center portion, and a substantially tubular upper portion which is plurally slotted to receive said vanes, said central and upper portions being proportioned to fit within the hollow cylindrical member of the magnetron anode electrode; a pin member disposed to pass through an axial hole in said body member, against which the inner edges of said vanes abut; a removable ring-like member having an inner diameter substantially the same as the outer diameter of the upper portion of said body member for embracing and retaining said vanes and for holding them in abutment with said pin member prior to insertion of said body member into the cylindrical electrode member, said ring-like member being forced past the slotted portion of said body member onto said upper portion by pressure of said cylindrical electrode member; a cap member for preventing said vanes from slipping out of said slots and for holding at least one of said ring-like conductors in proper relation to said vanes; and a retaining member for engagement with said pin member to clamp the aforesaid jig and electrode components into a rigid unit during the process of permanently uniting the electrode members.

2. A jig for assembling magnetron anode electrodes constructed of a hollow cylinder the interior portion of which is partitioned into resonating cavities by metallic vanes disposed substantially along radii of said cylinder, alternate vanes being connected by ring-like conducting members, comprising: said jig including a substantially cylindrical body member having radial slots in an end thereof for receiving said vanes; a removable ring for temporarily retaining said vanes properly in said body member, said ring having a height which is less than that of said vanes, and an inner diameter which is equal to that of said hollow cylinder; a cap member for maintaining at least a portion of said ring-like conducting members in the proper position relative to said vanes; an elongated retaining member which extends coaxially through all of the aforesaid jig members, said retaining member engaging the inner ends of said vanes and maintaining them in engagement with the inner surface of said ring; and a fastening member which engages with said retaining member to combine the various jig members into a unit after assembly.

References Cited in the file of this patent UNITED STATES PATENTS 1,684,947 Daumanu Sept. 18, 1928 2,247,077 Blewett et a1. June 24, 1941 2,257,643 Paschke et al. Sept. 30, 1941 2,306,291 Alons Dec. 22, 1942 2,310,841 Curtis Feb. 9, 1943 2,387,722 Dodge Oct. 30, 1945 2,408,238 Spencer Sept. 24, 1946 2,433,339 Brown Dec. 30, 1947 2,445,766 Derby July 27, 1948 2,447,491 Corley Aug. 24, 1948 

